This invention relates to a concrete elevation assembly formed of components or elements to enable a person to move from one elevation to another, a hollow concrete block utilized as a support for the concrete elevation assembly or as a wall, and a method for forming the hollow concrete block and, more particularly, to a concrete elevation assembly in which the components or elements may be easily assembled by one person in an interlocking relation, a hollow concrete block having the tolerances of its walls parallel to the longitudinal axis of a through passage closely controlled, and a method for forming the hollow concrete block so that its through passage may be disposed horizontal to have the tolerances of its support walls closely controlled.
The concrete elevation assembly may be either a step assembly or a ramp assembly. Each enables a person to move from one elevation to another.
Various step assemblies have previously been suggested in U.S. Pat. Nos. 744,887 to Walsh, 1,265,949 to Osborn, 1,475,777 to Ballenger, 1,879,996 to Sherwood, 2,153,017 to Henderson, 2,722,823 to Summers, 3,025,639 to Lemieux, and 3,706,170 to Argraves et al. The assembly of each of the aforesaid patents has disadvantages, particularly when the steps are to be assembled by an unskilled artisan such as a do-it-yourself person, who lacks both the knowledge and the tools to perform certain functions such as being able to form cement or mortar.
The aforesaid Walsh patent has risers and treads of steps formed of plastic and relies solely on cementing the risers and the treads to each other to hold them in place. It is not understood how plastic can be cemented to plastic. However, even if it could, a base-wall is formed as a single element beneath the width of the steps or as two elements at opposite sides of the steps. There is no interlocking of any of the risers, treads, and supports therefor in the aforesaid Walsh patent.
The aforesaid patent to Walsh also requires ledges on the inside of the base-wall, if it does not extend completely beneath the step structure, to support the risers, which have a hollow U-shaped cross section with a tread on top thereof.
For the do-it-yourself person, who is not a skilled artisan, the step assembly of the aforesaid Walsh patent would not be easy to form because of the problem of how to support the two base-walls. These would be extremely heavy when made of concrete blocks, for example, as the present invention uses in order to be able to have an easy assembly.
The aforesaid Osborn patent requires the assembly be held by a building. This requirement would prevent a do-it-yourself person from being able to utilize the structure of the aforesaid Osborn patent.
In addition, the aforesaid patent to Osborn has a complex arrangement for connecting risers, treads, and stringers to each other. This requires fresh cement to be poured in openings in the bottom surface of the tread registering with elongated openings in the stringers and an elongated opening in the top of the riser registering with a longitudinal opening in the bottom surface of the tread. This mixed fresh cement is normally not within the capabilities of a do-it-yourself person.
The step assembly of the aforesaid Ballenger patent also requires its connection to a building wall through a connector having a hook supporting the lowermost of the risers. The risers are supported solely by the treads of adjacent steps except for the lowermost of the risers. This prevents a free-standing step assembly.
The aforesaid patent to Sherwood has relatively large end rest members supporting opposite ends of each tread of a step assembly. During assembly, tie rods hold the end rest members together. Mortar also is required; this is not within the skill of most do-it-yourself persons.
Furthermore, the aforesaid Sherwood patent forms the risers with brackets to support the bottom of the treads, which are attached to the end rest members. However, there is no connection between the tops of the risers and the treads. Thus, the aforesaid patent to Sherwood has a rather expensive step assembly that cannot be formed by a do-it-yourself person.
The aforesaid Henderson patent employs hollow concrete blocks on which treads may rest with their ends supported by risers, which are supported by the hollow concrete blocks having vertical through passages. The risers and the treads are mortared to each other. The treads are supported intermediate two end sets of hollow concrete blocks by straps or plates, which are supported by the risers.
The aforesaid patent to Henderson lacks any means for properly aligning the elements together during assembly. Mortar is also required, and this is not satisfactory for a do-it-yourself person. Furthermore, the size of the concrete blocks is larger than any present building code as to height of a step.
The aforesaid Summers patent has relatively large side pieces, which would be difficult to handle if formed of concrete, for example, and requires tensioning rods to hold the assembly together. There is no direct connection of the risers and the treads although there are interlocking arrangements between the side sections and the treads and between the side sections and the risers. Mortar also is required to be in position prior to and after the assembly procedure is completed for the structure to be substantially integral. There also is a requirement for a tapered key to hold the tread in a locked position. This is a rather complex and expensive assembly. Because of the use of mortar, a do-it-yourself person could not effectively construct the assembly of the aforesaid patent to Summers.
The aforesaid Lemieux patent has stringers with tie rods connecting them together. Risers have their bottoms seated in notches in the stringers as are depending flanges on the rear of the treads. There is no interlocking of the treads to the risers or the stringers except for the disposition of the flange on the rear of each of the treads within the notch, which also receives the lower end of the riser supporting the tread thereabove.
The step assembly of the aforesaid patent to Argraves et al has no interlocking elements and requires both mortar and bolts to hold the assembly together. Mortar or other bonding agent connects a reduced portion of each tread to side members, which are stamped to look like individual pieces and have mortar applied in grooves formed thereby. Mortar also is required to be applied over the bolts.
The present invention satisfactorily overcomes the problems of the aforesaid patents through enabling a concrete step assembly to be easily erected by a do-it-yourself person. There is no requirement for mixing with any cement or other materials. Instead, only a construction adhesive, which may be easily applied by a do-it-yourself person through a caulking gun, is used.
Furthermore, an interlocking arrangement between the risers and the treads insures that each of the risers is positively locked or held in position.
The concrete elevation assembly of the present invention also may be formed as a concrete ramp assembly. The ramp assembly employs concrete support elements with each having only its top surface inclined and support structures for the concrete elements similar to the support structures of the concrete step assembly and having an interlocking arrangement with the concrete support elements.
The ramp assembly also may be formed with intermediate support elements disposed on substantially horizontal upper surfaces of concrete blocks with the intermediate support elements having an inclined upper surface and a horizontal lower surface, which rests on the substantially horizontal upper surface of each of the concrete blocks supporting it. Each of the intermediate support elements has an interlocking relation with each of the concrete blocks supporting it.
The inclined upper surface of each of the intermediate support elements supports planks, which have substantially parallel upper and lower walls. There is an interlocking relation between the inclined upper surface of each of the intermediate support elements and each of the planks supported thereby.
The invention contemplates preferably using only two different intermediate support elements with each having the same length. The two different intermediate support elements for the lowest portion of the ramp are supported on a single course of concrete blocks at least on each side of the ramp assembly. The next two different intermediate support elements are supported at least on each side on the substantially horizontal upper surface of each of the upper courses of two courses of concrete blocks. If more than four of the intermediate support elements are required at least on each side to support the planks, the next two different intermediate support elements would be supported on top of three courses of concrete blocks at least on each side.
Thus, utilization of an increasing number of courses of staggered concrete blocks for each pair of the two different intermediate support elements enables the use of only two different intermediate support elements as part of the ramp assembly. This reduces manufacturing costs.
In the preferred embodiment, the smaller of the two different intermediate support elements has a relatively small thickness such as 1xe2x80x3, for example, at its thinner end between its inclined upper surface and its horizontal lower surface and a thickness of 4xe2x80x3 at its thicker end. The larger of the two different intermediate support elements is formed with the same thickness of 4xe2x80x3, for example, at its thinner end and a thickness of 7xe2x80x3 at its thicker end. Therefore, there is a 3xe2x80x3 variation between the ends of each of the two different intermediate support elements. By having the adjacent ends of the two different intermediate support elements with the same thickness, a smooth inclined surface is produced by the planks, which preferably have a thickness of 2xe2x80x3, supported by the two different intermediate support elements.
Additionally, because the concrete blocks have a thickness of 6xe2x80x3, the smaller intermediate support element with the 1xe2x80x3 thickness at one end provides a total of 7xe2x80x3 when disposed on a second course of the concrete blocks. That is, the concrete block thickness of 6xe2x80x3, plus the 1xe2x80x3 thickness at the thinner end of the smaller intermediate support element equals the 7xe2x80x3, thickness at the thicker end of the larger intermediate support element against which the thinner end of the smaller intermediate support element abuts when supported by each of the second courses of the staggered concrete blocks.
The interlocking relation between the concrete blocks and the two different intermediate support elements is preferably provided by a single, relatively wide projection extending upwardly from the horizontal upper surface of each of the supporting concrete blocks being disposed within a relatively wide channel or groove in the horizontal lower surface of the smaller or larger intermediate support element. Similarly, the inclined upper surface of each of the larger and smaller intermediate support elements has a relatively wide projection for disposition in a relatively wide channel or groove in the lower surface of each plank, which it supports, on each side thereof.
This arrangement of the single projection and channel, symmetrically located, enables the intermediate support elements, the concrete blocks, and the planks to be interchangeable. This reduces the costs of manufacture and inventory.
The concrete blocks are preferably hollow concrete blocks having a horizontal passage extending therethrough. The walls of the hollow concrete block between which the through passage extends cannot have their tolerances closely controlled. This is because these two walls have movable elements (a press head and a pallet) of a block machine, which forms the hollow concrete block, pushing on the concrete material to form the hollow concrete block since all available block machines have the passage vertically disposed during formation.
The method of the present invention controls the tolerances of the walls parallel to the longitudinal axis of the horizontal through passage in the hollow concrete block. As a result, horizontal surfaces of the walls fit against the horizontal bottom surface of the intermediate support elements, which are wet cast, so that there is no space or gap therebetween requiring mortar to close as is presently required with hollow concrete blocks having the through passage disposed vertically.
Likewise, when the hollow concrete blocks are stacked on each other in a staggered relation, the horizontal surfaces of the engaging walls of two vertically spaced hollow concrete blocks fit tightly because of the controlled tolerances. This allows the hollow concrete blocks to be arranged in stacked courses as supports for the elevation assemblies of the present invention or as a wall without the need of any mortar. That is, when the hollow concrete blocks have previously been utilized with the through passage vertical as it is formed, the tolerance of neither of the walls, which are horizontal when the passage is vertical, between which the through passage extends can be satisfactorily controlled. As a result, mortar, which requires a skilled artisan for application, has to be utilized to compensate for this lack of tolerance control of the walls defining the top and bottom walls of each of the hollow concrete blocks when the through passage is vertical.
The use of the hollow concrete blocks also reduces the weight in forming the supports of the concrete elevation assemblies of the present invention. The hollow concrete blocks are much easier to handle than solid concrete blocks because of the reduced weight.
It has previously been suggested in U.S. Pat. No. 3,416,276 to Caputo et al to dispose hollow concrete blocks with passages extending horizontally therethrough. The aforesaid Caputo et al patent also recognized the need to avoid the use of mortar in joining the hollow concrete blocks to each other to form a plurality of staggered courses of the hollow concrete blocks forming a masonry wall, for example, to enable an unskilled person to erect the wall.
In the aforesaid Caputo et al patent, a top surface of each of the hollow concrete blocks has an arcuate central portion forming an arcuate tongue for cooperation with an arcuate groove in the same area of the bottom surface of a hollow concrete block thereabove. Each of the top and bottom surfaces includes a substantially flat surface on each side between which the arcuate tongue or arcuate groove extends. The flat surfaces on the top surface of one of the hollow concrete blocks engage the corresponding flat surfaces on the bottom surface of the hollow concrete block thereabove.
Prior to placing a hollow concrete block on top of a lower hollow concrete block in the aforesaid Caputo et al patent, an adhesive mortar is preferably laid in beads on the substantially flat surfaces of the top surface. Alternatively, the adhesive mortar could be applied in separate and discrete globs or with brushes, knives, or rollers.
While the aforesaid Caputo et al patent recognized that the adhesive mortar must be applied in minimal quantities so that no excess appears on the outer surfaces of the hollow concrete block or in the joints between the hollow concrete blocks, there is no explanation of how this minimum quantity can be controlled and still obtain good adherence between the hollow concrete blocks. For example, if more than a very slight amount of the adhesive mortar is applied, the substantially flat surfaces on the adjacent vertically stacked hollow concrete blocks will not touch each other but have at least a minimum space therebetween. If not enough of the adhesive mortar is applied to insure that the substantially flat surfaces engage, there may not be sufficient adhesive to join the hollow concrete blocks.
The present invention overcomes the foregoing problems of the aforesaid Caputo et al patent through controlling the height of the projection relative to the depth of the channel or groove in which the projection is disposed when two of the hollow concrete blocks are vertically stacked on each other. By controlling the spacing between the top of the projection and the base of the channel or groove, the amount of adhesive utilized to join the adjacent vertically disposed hollow concrete blocks is controlled.
Additionally, the present invention locates the area in which the adhesive is applied away from the outer surfaces of the hollow concrete block rather than adjacent thereto as in the aforesaid Caputo et al patent. This avoids the problem of the aforesaid Caputo et al patent of the engaging substantially flat surfaces of the adjacent vertically disposed hollow concrete blocks not having complete contact with each other. Furthermore, since the present invention controls the tolerances of these engaging flat surfaces, there will always be engagement therebetween because the amount of adhesive between the top of the projection and the base of the channel or groove is controlled.
An object of this invention is to provide a concrete step assembly capable of being assembled by an unskilled person.
Another object of this invention is to provide a concrete ramp assembly capable of being assembled by an unskilled person.
A further object of this invention is to provide a ramp assembly requiring only four different parts irrespective of the length of the ramp assembly.
Still another object of this invention is to provide a ramp assembly requiring only two different inclined elements irrespective of the length of the ramp assembly.
A still further object of this invention is to provide a method for forming a hollow concrete block with relatively close tolerances of its walls parallel to the longitudinal axis of its through passage.
Yet another object of this invention is to use hollow concrete blocks as the supports for a concrete elevation assembly.
Other objects of this invention will be readily perceived from the following description, claims, and drawings.